Optical endpoint detection system

Abstract

Methods and apparatus for determining an endpoint of a process chamber cleaning process are provided. In some embodiments, a processing system having an endpoint detection system may include a process chamber having internal surfaces requiring periodic cleaning due to processes performed in the process chamber; and an endpoint detection system that includes a light detector positioned to detect light reflected off of a first internal surface of the process chamber; and a controller coupled to the light detector and configured to determine an endpoint of a cleaning process based upon the detected reflected light.

The invention claimed is: 
     
       1. A processing apparatus having an endpoint detection system, comprising:
 a process chamber having internal surfaces requiring periodic cleaning due to processes performed in the process chamber; and 
 an endpoint detection system comprising:
 a light detector positioned to detect light reflected off of a material deposited on a first internal surface of the process chamber, wherein the reflected light does not traverse an internal volume of the process chamber; and 
 a controller coupled to the light detector and configured to determine an endpoint of a cleaning process based upon an interference pattern of the detected reflected light. 
 
 
     
     
       2. The apparatus of  claim 1 , further comprising:
 a light source positioned to shine light on the first internal surface. 
 
     
     
       3. The apparatus of  claim 2 , wherein the light source comprises a laser, a light emitting diode (LED), or a lamp. 
     
     
       4. The apparatus of  claim 2 , wherein the light source comprises ambient light. 
     
     
       5. The apparatus of  claim 2 , wherein the light source emits a single wavelength of light. 
     
     
       6. The apparatus of  claim 2 , wherein the light source emits a plurality of wavelengths of light. 
     
     
       7. The apparatus of  claim 2 , wherein the process chamber comprises a quartz lid, and wherein the light source is disposed outside of the process chamber and shines light on the first internal surface at a wavelength that passes through quartz. 
     
     
       8. The apparatus of  claim 1 , wherein the light detector comprises one or more of a photodiode or a camera. 
     
     
       9. The apparatus of  claim 1 , wherein the light detector is positioned to detect light reflected off of a lid of the process chamber. 
     
     
       10. The apparatus of  claim 1 , further comprising:
 a plurality of light sources and light detectors configured to measure a thickness of a coating of deposited material and cleanliness of the internal surfaces at different locations. 
 
     
     
       11. A processing apparatus having an endpoint detection system, comprising:
 a process chamber having internal surfaces requiring periodic cleaning due to processes performed in the process chamber; 
 a lid included in an upper portion of the process chamber and comprising one of the internal surfaces of the process chamber requiring periodic cleaning; and 
 an endpoint detection system comprising:
 a light detector disposed above the lid and positioned to detect light reflected off of a material deposited on an internal surface of the lid, wherein the reflected light does not traverse an internal process chamber volume; and 
 a controller coupled to the light detector and configured to determine an endpoint of a cleaning process based upon the detected reflected light. 
 
 
     
     
       12. The apparatus of  claim 11 , wherein the lid is made from quartz. 
     
     
       13. The apparatus of  claim 12 , further comprising a light source disposed above the lid that emits light at a wavelength that passes through quartz. 
     
     
       14. The apparatus of  claim 13 , wherein the light source comprises a laser, a light emitting diode (LED), or a lamp. 
     
     
       15. The apparatus of  claim 13 , wherein the light source provides light to a portion of the lid to determine the endpoint of cleaning for the portion. 
     
     
       16. The apparatus of  claim 11 , wherein the lid is dome shaped, reverse-curve shaped, or flat shaped. 
     
     
       17. A processing apparatus having an endpoint detection system, comprising:
 a process chamber having internal surfaces requiring periodic cleaning due to processes performed in the process chamber; and 
 an endpoint detection system comprising:
 a light detector positioned to detect light reflected off of a material deposited on an internal surface and light reflected off a corresponding external surface of a component of the process chamber; and 
 a controller coupled to the light detector and configured to determine an endpoint of a cleaning process based upon the detected reflected light. 
 
 
     
     
       18. The apparatus of  claim 17 , wherein a light source provides light to a portion of the component of the process chamber to determine the endpoint of cleaning for the portion. 
     
     
       19. The apparatus of  claim 18 , wherein the light source comprises a laser, a light emitting diode (LED), or a lamp. 
     
     
       20. The apparatus of  claim 2 , wherein the light source shines light to a portion of the internal surface to determine the endpoint of cleaning for the portion.